I would simply declare that in the specific case of the Jet spells, the Concentrate maneuver allows an attack as part of it. There isn't a tremendous amount of precedent for this, I'll admit, but I don't think it's unreasonable, either.

Can you use attack options with that attack? Feint?

I think that Fast-Draw turning a Ready into a Free Action is a precedent for something similar.

Maybe:Fast Jet: You can learn Fast-Draw (Jet) which if you succeed at allows you to cast Jet spells as a Free Action. You must specialize this perk for each Jet spell, and your Fast-Draw (Jet) skill works for any Jet spells you have the perk for.